We explain what a mill is, its origin, history and how it works. Also, the characteristics of each type of mill.
What is a mill?
a mill is a type of machinery that is used to harness kinetic energy. This energy can come from wind (wind or windmill), water (hydraulic or water mill), or animal traction (blood mill), to carry out mechanical tasks such as grinding materials or generating electricity.
In its agricultural version, intended for grinding edible grains, It is one of the oldest inventions of humanity which has different names depending on the region and the specific use given to it. Thus, for example, we speak of an almazarra for the mill used in olive plantations, and a trapiche or ingenio for the mill used to crush sugar cane.
Traditional windmills are a traditional part of the landscape in different geographies of Europe, and have been portrayed in artistic works as symbols of local culture, as is the case of the windmills in the Don Quixote by Cervantes, or in the Van Gogh series The Moulin de la Galette (1886).
Origin and invention of the mill
The first mills arose in ancient times, within the framework of the Neolithic Revolution in which agriculture was established as the main activity of humanity. were intended to crush cereals and grasses to produce flour but also some types of tubers, seeds and collected fruits.
Initially this work was carried out manually, with pestles and mortars made of different materials, which were used to crush the materials between two flat stones.
However, since it was an arduous and repetitive task, more expeditious and continuous methods were needed, which probably arose with the use of pack animals through rudimentary blood mills. In the absence of animals, it is likely that slaves were also used for this work, as evidenced by certain biblical and classical accounts.
The invention of the mill, in any case, is uncertain. The first historical description of one of these artifacts comes from the Pneumatics by the Greek engineer and inventor Philo of Byzantium (280-220 BC), and consisted of a water mill probably invented sometime in the 3rd century BC. c.
These hydraulic mills were also known by the Romans and used from the 1st century BC. C., judging by the descriptions made by Vitruvius (81-15 BC), the famous Roman architect and military man.
How does a mill work?
If we have ever used a pepper or coffee grinder, we will be familiar with the system that makes up the mills alike. It is, in principle, an instrument to convert one type of energy (kinetic, from wind or water, or biochemical, from living beings that push) into another (mechanical, from gears, or electrical, if there are turbines). usable for specific tasks.
In principle, a mill It has a set of blades fixed to a rotating axis. When wind or water pushes on the specially designed blades, they rotate the shaft, which in turn transmits, through a colossal gear, its movement to another horizontal axis at the end of which there is a mobile stone, circular in shape, called a grinding wheel.
The latter, when rotating on its axis, crushes everything that is poured underneath: grains, cereals, olives, sugar cane, etc., thus allowing flour, juices or oils to be obtained, as the case may be.
This principle operates regardless of whether the mill depends on wind, river water, or coastal tide. It is applied in a similar way in the case of windmills intended to produce electricity, with the exception that, instead of the grinding wheel, these devices have an electric turbine and generator, in order to transform the movement into electricity.
Types of mill
Mills can be classified according to the type of energy they use:
- Blood mills. When it is the force of an animal (or people) that mobilizes the rotating axis of the mill.
- Windmills When it is the force of the wind that blows that mobilizes the blades of the mill.
- Water mills When it is the force of a river that moves the blades.
- Combustion mills When the force that moves the shaft comes from the combustion of chemical substances (fuels).
- Electric mills When they consume electricity to move the rotating axis.
They can also be classified according to the task performed, into:
- Grinding mills When they have a grinding wheel to crush and transform food.
- Generating mills When they have the task of activating electricity generation turbines.
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References
- “Mill” on Wikipedia.
- “Windmill” in Enciclopedia.us.
- “What does a windmill have inside?” (video) on RTVE (Spain).
- “Windmill” (video) on ABC Rural Paraguay.
- “History” at Third Planet Windpower.
- “Windmill” in The Encyclopaedia Britannica.
